Dark clouds are forming. With apologies to Billy Joel, to be in a New York State of Mind is to have a sense of dread.

That’s because the Democratic candidates for mayor are on the prowl. They say they love the city, just not the way it is. They want to fix it.

Heaven save us from their “reforms.”

Their Big Idea is to slice the Police Department into pieces, then wrap them in red tape. If they succeed, they risk reversing the single most important achievement in modern Gotham history.

The decline of crime over the last 20 years saved lives and saved New York by giving people the time and confidence to remake their homes and live their dreams. Salvation came after cynics said it couldn’t be done, that New York was a doomed Rotting Apple.

But it was done and the 80 percent cut in murder and other violent crimes set in motion a circle of virtue that continues to pay dividends.

Public safety allowed law-abiding citizens to take back streets, parks and subways. Just as crime causes poverty, safety prompts investment.

The investment of dollars and sweat revived neighborhoods, created jobs and improved life for millions of people. It created a tsunami of tax revenue that funded schools, infrastructure and, yes, those dopey bicycle lanes.

Safe streets attracted tourists, who came to see the sights or a show knowing they weren’t risking their lives. In hindsight, the idea that major parts of the city, including Times Square, would always remain seedy and dangerous seems ridiculous.

That counsel of surrender was, thankfully, ignored by Rudy Giuliani and Michael Bloomberg. Under their watch, the letters “NYPD” became a badge of honor, known the world over for professionalism and excellence. To be a New York cop is to wear a white hat, to be the good guy. The department’s strategies and tactics are a model for policing everywhere.

But things that got better can also get worse. As Bloomberg says, the move to handcuff the NYPD with an independent inspector general “is one of the worst-conceived ideas.”

But the mayor himself is naive when he dismisses the motives of leading mayoral candidate Christine Quinn, the City Council speaker, and others supporting the measure. Said Bloomberg on WOR Radio: “It’s the first time I’ve ever seen people who want to be the executive try to denude the office before they get it.”

Note to Bloomy: Shrinking the mayoralty is precisely the aim. While the creation of an inspector general certainly is a campaign stunt, it doesn’t end there. The office — with broad powers to investigate wrongdoing and second-guess the police commissioner’s strategy, tactics and personnel decisions — would help insulate a mayor eager to duck criticism.

Protection from responsibility is not a side effect of the medication. It’s the prescription.

Committed liberals like Quinn want the benefit of low crime, but not the job of achieving it and certainly not the accountability when things go wrong. The attack on stop-and-frisk is another front in their war against the NYPD.

Cops shot 28 people last year. In context, that’s a remarkably low number, down from 90 in 1994. Yet each and every shooting could draw heat and damage a mayor politically.

Bloomberg, much like Giuliani before him, instinctively defends cops, or at least urges patience and the benefit of the doubt.

It comes from recognizing the life-and-death dangers of police work and knowing that even good cops making split-second decisions can make fatal mistakes. Most important, being mayor means understanding that the thin blue line is all that stands between civilization and chaos.

But if you don’t see the cops as a force for good, if you see them as an occupying army, or just aim to appease New Yorkers who do, then the inspector general is a perfect answer.

It’s a hiding place for a mayor afraid to take a stand. It’s a duty-free zone for a mayor with a penchant for pandering.

After a shooting or some other controversy, a weak mayor could “demand” a probe by the IG, then slink off into the shadows while the heat falls on the commissioner. And when the IG, perhaps with an agenda of his own, rips the department, the cowardly mayor’s hands will be washed clean of all responsibility.

That’s the purpose of this destructive agenda. To win the election, then duck the burdens of office.

Checking up on Albany $$ depravity

There is little good news in the state budget, but the plan to mail relief checks next year stands out as spectacularly depraved. Spreading the wealth around doesn’t get more bald-faced.

The handout would give the vast majority of households as much as $500 each. Because the checks would arrive in an election year, the clear message is that a vote for incumbents is expected.

But Albany doesn’t have $150 million to give Paul until it robs Peter, so the budget extends a surcharge on high-income New Yorkers and a tax on electricity bills, both of which were set to expire.

Senate Republicans, who claim to stand for limited government, stand exposed again as incorrigible quislings. Gov. Cuomo’s double-talk about whether a tax extension is a tax hike makes him look foolish.

The taxes, coupled with rising federal rates, will lead more New Yorkers to seek friendlier climes, shifting a greater tax burden to fewer suckers. A tipping point is inevitable.

Still, there is a winner, and that would be Assembly Speaker Sheldon Silver. He remains the straw that stirs Albany and his commitment to ever more spending and taxing carries the day.

Congratulations to him, and condolences to his victims.

Jewish theater

President Obama’s trip to Israel was brilliantly staged and his speech to Jewish students a model of flattery and persuasion. But when the swooning ended, his policy message was predictably pedestrian.

Best summarized as “be nice to Palestinians,” he spoke as terror groups launched missiles from Gaza. Even he was denounced by Arabs as a Zionist tool.

Obama can’t tolerate Americans who criticize him, but wants Israelis to make concessions to people trying to kill them. He doesn’t know Yiddish, but certainly has chutzpah.

Dishonoring all students

This just in: March Madness has been canceled. Officials are worried that losing players will have their feelings hurt.

That’s the future if Massachusetts principal David Fabrizio ever runs the NCAA. The head of Ipswich Middle School is ending an event that singled out top students.

“The Honors Night, which can be a great sense of pride for the recipients’ families, can also be devastating to a child who has worked extremely hard in a difficult class but who, despite growth, has not been able to maintain a high grade-point average,” Fabrizio wrote to parents.

Chalk up another victory for mediocrity in the war against excellence.